Energy Storage Permitting Guidebook - Report - Page 17
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Energy Storage Guidebook
The current installation codes and standard requirements for ESS in the United States, related to fire and
explosion testing, are the 2023 edition of NFPA 855 and the 2024 edition of the International Fire Code,
which require fire and explosion testing to be conducted in certain situations. Both editions reference that
such testing shall be conducted on a representative ESS in accordance with UL 9540A, the Standard for Test
Method for Evaluating Thermal Runaway Fire Propagation in Battery Energy Storage Systems.
Key considerations for fire safety and installation of ESS, primarily for commercial and multifamily systems,
include:
Location and Installation: NFPA 855 recommends that ESS be installed in locations compliant with
applicable building and fire codes. Systems should be installed away from combustible materials and
in areas with proper ventilation to dissipate combustible gases.
Battery Chemistry: Different battery chemistries have varying risks and requirements. Lithium-ion
batteries, commonly used in ESS, require specific handling and safety precautions due to their thermal
runaway potential.
Thermal Management: Effective thermal management systems are crucial for preventing overheating
and thermal runaway in ESS.
Fire Detection and Suppression: NFPA 855 recommends the installation of fire detection or suppression
systems, such as smoke detectors and automatic fire sprinkler systems, to quickly detect and mitigate
fire incidents.
Emergency Response Plans: Developing comprehensive emergency response plans is essential for
effectively managing fire incidents involving energy storage systems. This includes training personnel
on proper response procedures and coordinating with local fire departments.
Compliance and Certification: ESS must undergo rigorous testing and certification processes to ensure
compliance with safety standards such as UL 9540, UL 9540A, and NFPA 855. Compliance with these
standards is often a requirement for obtaining permits for installation and operation.
Fuel load in residential systems is limited to 20 kWh per unit. This is the primary fire protection strategy
outside of internal barriers in the ESS for fire risk mitigation.
By adhering to these standards and best practices, stakeholders can mitigate the risks associated with ESS
and ensure the safety of occupants, responders, and surrounding environments. Effective regulation and
compliance play a crucial role in promoting the widespread adoption of energy storage technologies while
maintaining high standards of safety and reliability. (For more information on UL 9540, 9540A, and NFPA,
855 please see the training on Resources page.)
UL 9540 Certification
UL 9540, the Standard for Safety of Energy Storage Systems and Equipment, covers electrical,
electrochemical, mechanical, and other types of energy storage technologies for systems intended to supply
electrical energy. The Standard covers a comprehensive review of ESS, including charging and discharging,
protection, control, communication between devices, fluids movement and other aspects. UL 9540 was first
introduced in 2016 and has undergone revisions. The current edition of UL 9540 referenced in the CEC is the
2nd edition dated February 2020 with revisions through April 2021. NFPA 70, the National Electric Code®
(NEC®), the International Residential Code (IRC), the International Fire Code (IFC), and NFPA 855 Standard for
the Installation of Stationary Energy Storage Systems all require ESS to be listed and labeled in accordance
with UL 9540.
If a product is UL 9540 listed, this means the ESS meets a specific set of standards for safe operation
published by UL Solutions. UL 9540 is a system-level evaluation of ESS. It ensures that all components of
the ESS are compatible with each other, as well as the environment in which they are installed. Individual
